Spatial Manipulation basically distorted the dimensions of certain places inside of some objects. Although it was more accurate to say that Leon just surprised a certain space and sealed inside an item, Leon was pretty sure that the inverse could be done... in case someone gets trapped in a spatial trap.
"The problem is, I don't have much time to do this," Leon said. "The dragons are getting stronger by the day... much faster than me. If I use my mana to create weapons, I can counter that effect, but since I will need a lot of it to leave this place, I will end up putting myself in a dire situation if I fail."
In the end, Leon created a mithril spear that would help him along the way against dragons and that he would absorb to use Spatial Manipulation to its limits. If he fails, he would have a lot of trouble, but not much as if he tries to consume his only mithril weapon.
